Articles of footwear, in particular, athletic shoes, can be thought of as having two major components, an upper and a sole. The upper is secured to the sole and provides a cavity for receiving a foot. The upper is generally formed from multiple elements stitched or adhesively bonded together to form a structure for comfortably receiving a foot. In addition, the upper also includes a lacing system which, when loosened can allow the cavity for receiving the foot to expand to permit feet of varying sizes to fit into the cavity. The lacing system can then be secured to pull the upper in to surround the foot and secure the shoe to the foot. A tongue portion, covering the top of the foot and extending under the lacing system may also be included. The tongue is stitched to the upper and enhances the comfort of the shoe.
The sole is the interface between the foot and the ground and is intended to provide traction, support and cushioning for the user. Many soles have a multi-part construction including an outsole and a midsole. The outsole is generally designed for durability and traction. The midsole is commonly designed to absorb the force created as the shoe contacts the ground. The sole may be flexible to cater to the intended purpose of the shoe. For example, shoes made particularly for use in dancing or dance-related activities may include a flexible sole to allow for various dance or dance-related foot movements. A wearer of conventional street shoes must change to dance shoes to go from the street to the dance studio.